It doesn't even need to know what kind of signal it's looking at, and it can get its position in places there's no GPS to work from, whether it's in an urban canyon or the natural kind.
The GAARDIAN consortium, which completes its work this month, has developed equipment to provide real-time information about the reliability of GPSat airports or other sensitive locations using networks of probes.
The voice turn-by-turn navigation, GPS tracking and traffic updates are handy to have and all work well, but those are staples for any OS at this point, which means they aren't standout features.